Fluff Linux Update

Fluff Linux Update is the native KDE Plasma 6 update experience for Fluff Linux. It lives in System Settings, can also be opened from the application menu, and keeps manual system updates clear and approachable.

What it can do

• Check for system updates without changing the real pacman database.
• Show the total download size and expected storage change.
• Preview every package and its old and new version before installation.
• Install updates through polkit using pacman -Syu --noconfirm.
• Show live download size, speed, installation progress, and completion.
• Continue an update in the background if the panel is closed.
• Reconnect to an update already in progress when the panel is opened again.
• Detect another running pacman process and handle a stale database lock.
• Protect important packages when an update proposes removing them, ask before removing warning-class packages, and automatically clear approved obsolete blockers.
• Preserve unmanaged files that conflict with an update, then restart the interrupted installation automatically.
• Allow downloads to be cancelled while protecting the installation phase.
• Warn laptop users when the system battery is low.
• Read the last successful update time from /etc/pacman.d/lastupdate.json.
• Follow the Plasma theme, scale with the window, and support RTL layouts.

The interface includes every official European Union language together with Arabic, Hebrew, Japanese, and Russian. English remains the source language.

The new package-recovery dialogs introduced in the 1.2 testing build are currently English only while their wording and behavior are being reviewed.

A quick look

Preview updates	Download updates

Install updates	Finished

Build on Fluff Linux or Arch Linux

Install the build requirements:

sudo pacman -S --needed base-devel cmake extra-cmake-modules \
    qt6-declarative kcmutils ki18n kcoreaddons kirigami \
    pacman-contrib polkit

Configure and compile:

cmake -S . -B build \
    -DCMAKE_BUILD_TYPE=Release \
    -DCMAKE_INSTALL_PREFIX=/usr \
    -DCMAKE_INSTALL_LIBDIR=lib
cmake --build build

If an older copy was built in the same directory, remove build/ and fakeroot/ first. The QML interface is embedded in the compiled KCM, so an old build directory can retain outdated resources and cached non-Arch installation paths.

Stage for packaging

Fluff Linux packages are assembled from a fakeroot instead of being installed directly onto the build machine:

# fakeroot/ becomes the package filesystem and can be passed to the Fluff Linux packaging tools.
DESTDIR="$PWD/fakeroot/" cmake --install build

Everything that belongs in the package will now be under fakeroot/, beginning with fakeroot/usr/. The package-removal policy is staged separately at fakeroot/etc/pacman.d/flufflinux-update-package-protection.json. This directory is only a packaging workspace; it is not a privileged chroot and staging into it does not modify the host system.

Use a clean fakeroot/ for each package build so files removed in a newer version cannot remain in the finished package.

Test locally

On a disposable development system, the staged build can instead be installed directly:

sudo cmake --install build
sudo systemctl daemon-reload
kcmshell6 kcm_fluffupdates

The panel appears as System Updates near the top of the System category. The application launcher also provides Check for system updates.

Repository replacements intentionally have no dialog. Automatic removals show a temporary informational note naming the removed package.

Languages

Translations are stored in po/<language>/kcm_fluffupdates.po and installed automatically during the packaging step. The translator-friendly string guide is available in po/README.md.

To verify the staged translation catalogs:

find "$PWD/fakeroot/usr/share/locale" \
    -path '*/LC_MESSAGES/kcm_fluffupdates.mo' -print

The corresponding system locale must also be generated on the installed system. Fluff Linux Update includes its translation catalogs but does not change the operating system's locale configuration.

Project branches

• main contains release-ready code used to build the Fluff Linux package.
• staging contains tested pre-release changes and is the normal target for community pull requests.

Development changes are tested locally before they are added to staging.

State and logs

Fluff Linux Update uses files under /etc/pacman.d/:

• lastupdate.json records the last successful system update.
• flufflinux-update-state.json lets the panel reconnect to an active update.
• flufflinux-update.log contains the latest pacman update log.
• flufflinux-update-package-protection.json defines protected, warning, and autoremove classifications. Packages absent from the file use autoremove.

Repository signing-key recovery is fail-closed. If pacman reports a complete unknown signing-key fingerprint that pacman conclusively attributes to the fluffnet repository, FLU downloads FluffNet's public certificate and expected primary fingerprint directly from fluffnet.org. It parses the certificate in an isolated disposable GnuPG home, rejects private-key material, verifies the primary fingerprint, key usability, self-signatures, and any signing-subkey binding, and only then merges the verified certificate into Pacman's keyring so rotated signing subkeys are refreshed. It re-inspects the exact requested key in Pacman's configured live GnuPG home before locally trusting the primary key through the existing privileged helper, then retries Pacman exactly once. That Pacman retry is the definitive check that the refreshed signing material can verify the repository metadata. It never contacts a third-party keyserver, changes global GnuPG configuration, or accepts pacman's key prompt. Failures from other or unidentified repositories do not trigger any FluffNet request or keyring change. Recovery currently accepts only the full 40-character OpenPGP v4 fingerprint format used by FluffNet's signing certificate; short key IDs do not authorize a recovery.

The published certificate may contain multiple signing subkeys. FLU accepts the exact requested usable subkey when it is validly certified by the currently published primary, rather than hard-coding one subkey fingerprint. A singular primary-key cutover is also supported within this HTTPS recovery model: if the same stable endpoints publish a new primary fingerprint and matching certificate, FLU can add and locally trust that new primary even when the machine only has an obsolete or expired old primary. The old primary is retained, and one Pacman retry remains the definitive verification. Only one published primary generation is authoritative at a time; this is not an overlapping or cross-certified multi-primary rotation protocol. Long-offline recovery still requires working HTTPS, compatible GnuPG/Pacman tooling, an initialized Pacman keyring, and the current 40-character OpenPGP v4 fingerprint format.

The isolated signing-key tests use disposable OpenPGP keys and mocked fingerprint endpoint, certificate endpoint, and Pacman-key operations:

cmake -S . -B build-tests -DBUILD_TESTING=ON
cmake --build build-tests
ctest --test-dir build-tests --output-on-failure

The existing lastupdate hook provides this field:

{
  "last_successful_system_update": "2026-07-20 14:30:00 IDT +0300"
}

Planned next steps

• A detailed failure dialog.
• Reboot recommendations after kernel or hardware-driver updates.
• Optional update notifications.

License

Fluff Linux Update is available under the MIT License.